<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <meta http-equiv="X-UA-Compatible" content="ie=edge">
    <title>色字</title>
    <style>
        .box{
            width:200px;
            height: 200px;
            background: #fff;
            padding: 20px;
            border: 2px solid #000;
            border-radius: 10px;

            display: flex;
           justify-content: space-around;
        }
        .item {
            width: 40px;
            height: 40px;
            border-radius: 50%;
            background: #999;
        }
        .item:nth-child(2) {
            align-self: center;
        } 
        .item:nth-child(3) {
            align-self: flex-end;
        } 
    </style>
</head>
<body>
    <div class="box">
        <div class="item"></div>
        <div class="item"></div>
        <div class="item"></div>
    </div>
</body>
</html>